SAN DIEGO (AP) — Groups trying to overturn a new California law allowing transgender students to choose public school restrooms and sports teams that correspond with their expressed genders have filed a lawsuit claiming state officials are unfairly refusing to count signatures seeking a referendum.

Sacramento-based Privacy For All Students, a coalition of conservative groups, filed the lawsuit Thursday against the secretary of state and two counties.

It says a courier delivered signatures collected in Tulare ahead of a deadline of Sunday, Nov. 10, but offices were closed early before the three-day Veterans Day weekend. In Mono County, a courier dropped the signatures in a county mail slot a day before the deadline, but workers did not return to their jobs until the deadline had passed, according to the plaintiffs.

The plaintiffs say the secretary of state’s office is refusing to validate the signatures from the two counties.

The secretary of state’s office did not immediately return phone calls on Friday seeking comment.

Opponents of the law that goes into effect on Jan. 1 said they have collected enough signatures for an initiative that would repeal it. Counties, however, were still reviewing the signatures.

The state previously said an early random sampling from counties via the secretary of state’s office found only 77 percent of the signatures qualifying.

The coalition submitted 620,000 signatures to get the initiative on the November 2014 ballot, said Frank Schubert, political strategist handling the signature gathering effort.

To qualify, at least 505,000 valid signatures of registered voters must be verified through a random sampling. After that, it is likely the state would order a full review before the measure could be place on a ballot.

California is the first state to pass a law allowing such choices by transgender K-12 students.

One provision gives them the choice of playing on boys or girls sports teams. It also allows them to choose which restroom they use.

Opponents say the law would violate the privacy of the majority of students and some might try to claim to be another gender simply to gain access to bathrooms.

School officials say decisions would be made under careful scrutiny involving parents, counselors, teachers, staff and the student.

The goal of the law is to reduce discrimination against transgender students.